Funds are requested for a multiuser computerized motion analysis system. The system consists of four image processing and graphics analysis workstations linked via ethernet to a central processor and file server, a Sun Microsystems SPARCstation330. Software will be the 2-D ExpertVision System (EV) for the analysis of cell and particle motion, and the Dynamic Morphology System (DMS) for the analysis of cell shape changes (both from Motion Analysis Systems, Inc.). One Zeiss Axiovert 35 microscope is also requested for highly resolved differential image contrast (DIC), phase, darkfield, and fluorescence images. The main applications will be to analyze (i) phototaxis signaling by rhodopsins in Halobacterium halobium and Chlamydomonas reinhardtii, (ii) excitation signaling in chemotaxis of Escherichia coli using photolabile caged chemoeffectors, (iii) chemotaxis and cell shape changes in Dictyostelium discoideum, (iv) membrane motors in bacteria and in squid axons, and (v) swimming behavior of intact and permeabilized paramecia. The major user group is comprised of Drs. Spudich, Condeelis, Khan, Satir, and Segall. The requested hardware and software will incorporate existing components of limited capability from our individual laboratories into a multistation motion analysis network with nearly two orders of magnitude greater computational speed.